Accompanying the rising age of hopeful parents is the increasing use of assisted reproductive techniques such as frozen embryo transfer (FET), intracytoplasmic sperm injection (ICSI), gamete intrafallopian tube transfer (GIFT), and zygote intrafallopian tube transfer (ZIFT). All these techniques, however, require proper implantation of the embryo and full term development to achieve a successful pregnancy.
Implantation and placentation are complex processes involving hormonal, immune, and anatomical changes in the mother and migration and cellular division of the embryo. Various uterine pathologies, such as thin endometrium, altered expression of adhesive molecules and immunological factors, may be the causes for repeated implantation failure.
Spontaneous abortion occurs in 15%-50% of diagnosed pregnancies in women between fifteen and forty-five years of age. The formal definition of recurrent spontaneous abortion is three or more spontaneous abortions. However, the American College of Obstetrics and Gynecology recommends that in women over the age of 35, a thorough workup should be undertaken after two spontaneous abortions. Approximately 3-4% of women are estimated to fit the formal definition of recurrent spontaneous abortion. The risk of pregnancy loss increases from 15-20% in the first pregnancy to 40% after one spontaneous abortion.
Although many pregnancies lost in the first trimester are due to fetal causes; spontaneous abortion, the loss of the products of conception prior to the 20th week of pregnancy, is often a disorder of unknown etiology. It has been theorized that spontaneous abortions are a natural rejection of a fetus with abnormalities incompatible with life; however, this theory has yet to be substantiated.
Risk factors for spontaneous include age, weight and overall health of the woman. The prevalence of spontaneous abortion increases with increasing maternal age, although not with gravidity. The risk begins to increase rapidly at age 35 years. The risk of spontaneous abortion at age 40 is approximately twice that at age 20. As families are planned later and later in life, the frequency of spontaneous abortion will only increase without effective methods of prevention.
Threatened abortion generally presents as cramping and bleeding for which treatment is bed rest. This conservative treatment provides palliative care for the mother but does little to alter the outcome. The use of hormones is generally contraindicated due to the risk of congenital anomalies, including malformation of the vessels of the heart of the embryo and possible genital abnormalities in female offspring.
In addition to the physical toll of these disorders, the loss of a desired pregnancy takes a tremendous emotional toll on hopeful and expectant parents. Loss of a pregnancy can lead to feelings of inadequacy, hopelessness and guilt which can have a devastating effect on individuals and on a marriage.
New methods and compositions are always needed to reduce risks associated with pregnancy to the health of the mother and fetus. Effective prevention of implantation failure or spontaneous abortion can allow women, especially women at risk, to have successful pregnancies. In particular, effective prevention of these disorders in women who suffer from infertility can allow women, especially women who seek medical care in the form of assisted reproduction like FET, ICSI, GIFT and ZIFT to have successful pregnancies. Prevention of implantation failure during assisted reproduction allows successful pregnancies, reduces the risks to women, and saves time and money.